file 操作 name creat 抽象 order by pad wait depend

• 業務字段設計

• 數據庫創建 • CRUD操作 • MyBatis集成 • 註解和XML定義 • ViewObject和DateTool • 首頁開發 • 業務字段設計 實體：

• 數據庫創建 GUI版本管理工具創建，然後通過GUI轉SQL； • CRUD操作 insert into table_name (列1, 列2,...) VALUES (值1, 值2,....)； select 列名1，列名2 from 表名稱 where 條件； 條件： between 1 and 2 order by 3 desc UPDATE 表名稱 SET 列名稱 = 新值 WHERE 列名稱 = 某值 • MyBatis集成 1. application.properties增加spring配置數據庫鏈接地址 spring.datasource.url=jdbc:mysql://localhost:3306/wenda?useUnicode=true&characterEncoding=utf8&useSSL=false spring.datasource.username=root spring.datasource.password=qwertyuiop mybatis.config-location=classpath:mybatis-config.xml 同時：在配置的同級別目錄下：resources/templates建立粘貼建立官網有：mybatis-config.xml <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <settings> <!-- Globally enables or disables any caches configured in any mapper under this configuration --> <setting name="cacheEnabled" value="true"/> <!-- Sets the number of seconds the driver will wait for a response from the database --> <setting name="defaultStatementTimeout" value="3000"/> <!-- Enables automatic mapping from classic database column names A_COLUMN to camel case classic Java property names aColumn --> <setting name="mapUnderscoreToCamelCase" value="true"/> <!-- Allows JDBC support for generated keys. A compatible driver is required. This setting forces generated keys to be used if set to true, as some drivers deny compatibility but still work --> <setting name="useGeneratedKeys" value="true"/> </settings> <!-- Continue going here --> </configuration> 2. pom.xml引入mybatis-spring-boot-starter和mysql-connector-java <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>1.1.1</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> </dependency> 3. 官網：http://www.mybatis.org/mybatis3/zh/index.html DAO層建立modul相關的userDao來通過mybatis訪問數據庫庫: //註解配置； @Mapper public interface UserDAO { String TABLE_NAME = "user"; String INSET_FIELDS = " name, password, salt, head_url "; String SELECT_FIELDS = " id, name, password, salt, head_url"; //通過抽象，實現crud的復用； @Insert({"insert into ", TABLE_NAME, "(", INSET_FIELDS, ") values (#{name},#{password},#{salt},#{headUrl})"}) int addUser(User user); @Select({"select ", SELECT_FIELDS, " from ", TABLE_NAME, " where id=#{id}"}) User selectById(int id); @Select({"select ", SELECT_FIELDS, " from ", TABLE_NAME, " where name=#{name}"}) User selectByName(String name); @Update({"update ", TABLE_NAME, " set password=#{password} where id=#{id}"}) void updatePassword(User user); @Delete({"delete from ", TABLE_NAME, " where id=#{id}"}) void deleteById(int id); } //xml配置，在相應的resources下建立DAO相應目錄的的xml； <mapper namespace="com.nowcoder.dao.QuestionDAO"> <sql id="table">question</sql> <sql id="selectFields">id,title, content,comment_count,created_date,user_id </sql> <select id="selectByUserIdAndOffset" resultType="com.nowcoder.model.Question"> SELECT <include refid="selectFields"/> FROM <include refid="table"/> <if test="userId != 0"> WHERE user_id = #{userId} </if> ORDER BY id DESC LIMIT #{offset},#{limit} </select> </mapper> • 註解和XML定義 • ViewObject和DateTool • 首頁開發

數據庫CRUD操作以及MyBatisd的配置使用